1. Field of Invention
This invention relates to the necessity of establishing perpendicular quill and spindle alignment with respect to the work table of vertical milling, boring, and drilling machines with single or multiple axis adjustable heads.
2. Description of Prior Art
Milling is a process of material removal by a single point or multiple point rotating cutter. Most milling machines can be categorized into the following basic groups: (a) Knee and column type, (b) Bed type, (c) Rotary type, (d) Planer Type.
The Knee and column type milling machines are produced in three basic designs: (a) Vertical, (b) Horizontal, (c) Universal. These basic machine tools are utilized for both production and toolroom work because they are vesitile and relatively easy to operate. For many years these machines have been produced around the world, and up until about 60 years ago, these machines had fixed vertical and horizontal quills. The quill assembly contains the rotating spindle and can be extended or retracted into the milling machine's head assembly. During this period, machine tool manufacturers began to produce vertical knee type milling machines with adjustable angle heads. The vertical knee and column type mill with adjustable angle head allows the operator to mill, drill, ream, and bore material at compound angles. The advantage of the adjustable angle head is great in that it can be adapted to a variety of complex set-ups very quickly. One disadvantage, however, is that once the head is moved to accomodate angle type milling, the head and its respective quill assembly must be squared with respect to the work table of the mill in order to perform straight precision boring.
With reference to vertical quill alignment; currently it is accomplished by chucking a rigid "L" shaped rod of approximitly 15 mm in diameter and 100 mm in length on its minor length or chucking side, and 150 mm in length on its major length or indicator end.
A precision dial indicator of 0.0001" graduations is mounted to the end of the major length of the "L" shaped rod with the minor length chucked into the nose of the spindle. The support rod with dial indicator is then adjusted so that the indicator is "touched off" on the surface of the work table. The indicator is then rotated through 360.degree. to show "total indicated run out" or T.I.R. on both the transverse axis or "y-axis", and longitudinal axis or "x-axis" of the table. By manipulation of the head adjustment and clamping bolts, a total indicated run out of zero on the face of the dial indicator is desirable, on both the transverse and longitudinal axis' of the table. Final head alignment is achieved by repeated rotation of the dial indicator over 360.degree. and repeated manipulation of head adjustment bolts.
The previously described process is time consuming and requires a high degree of skill and concentration on part of the operator. This process takes between 30 to 45 minutes typically, and does not guarantee alignment of the head and its' respective quill assembly for the following reasion: After head alignment is achieved, the operator must then make final tightening of the head clamping bolts. Often upon final tightening, the head will move out of perpendicular alignment, and the operator must start the entire process from the begining.
An alternate method of spindle squaring is achieved by extending the quill assembly completly out and then locking it. A precision machinist square is then set upon the work table with the blade of the square set parallel to the outside of the quill along the longidudinal and transverse axis' of the table. The head clamping and adjustment bolts are manipulated until visual quill perpendicularity with respect to the square is achieved. This method usually provides unsatisfactory alignment of the quill for precision boring, and is not often used.
The last and least satisfactory method of perpendicalar quill alignment is made by adjusting the head collar with factory stamped hash marks on the side of that collar. This method again allows the mill to be used for roughing work only.
All of the previously discussed alignment problems are directly attributed to the inability to mechanically hold the head and its respective quill assembly square with respect to the work table while the head clamping bolts are secured. At best, only random success is achived without the ability to secure the quill and head before final clamping.
It is my belief after a rigorous search, that the present invention is completly unique, and there is no prior art directly germane to my invention. Prior alignment methods employed the use of common machine shop measuring instruments such as indicators, squares, rods, and wrenches.